Most machinery, or other devices which have movable parts, rely on bearings to support, align, and allow free rotational or other movement of the supported members or of the bearings themselves. Consequently, many different types of bearings, and lubrication systems for these bearings, have been developed, all endeavoring to keep maintenance and repair operations and expenses to a minimum while maximizing performance. Oil is the normal lubricant used, and the bearing surfaces and the supported members are generally composed of metal, plastic, or other material.
The bearings are essential to performance and most require regular maintenance including repair and/or replacement where necessary. Also required is regular lubrication, or permanent lubrication and sealing, due to the bearing's movement or its function of supporting movable elements. Friction must be avoided or minimized to prevent wear and subsequent failure of the bearing or of the supported member and to deliver optimum performance during operation. Maintenance operations, including repair and/or replacement of worn members, can entail substantial down time during the maintenance operation, and frequently include expensive replacement costs for the worn members since their efficient performance is necessary. Maintenance operations can be an especially troublesome problem and the costs can be greatly multiplied on those members which are internally located in the particular machinery or where the machinery itself is in a remote location. Thus, consideration must also be given to the personnel and travel costs involved and to the concomitant loss of production and time.
Special problems are also encountered with bearings that must operate in cold environments, either within the machinery itself, or in cold regions of Earth, or in outer space. Colder temperatures reduce the viscosity of the lubricant and special precautions, pre-heating assemblies, or the like, are required to assure that the lubricant is sufficiently fluid to function properly. Without such safeguards, insufficient lubricant will reach the bearing surfaces upon initiation of movement, causing early wear and deterioration of the affected elements. The aforementioned problems encountered by bearings in normal environments are greatly multiplied in these extreme, cold environments.